Great Moments In Science

3 comments March 1st, 2007at 11:54am Posted by Eli

Oh my.

Promiscuity is common among female rodents, leading to competition between the sperm of rival males over who fertilizes the eggs. It now seems that possessing a longer penis may give males an advantage in this competition, according to new research to be published in the March issue of The American Naturalist. Dr. Steve Ramm, an evolutionary biologist at the University of Liverpool, UK, compared the relative size of the penis bone in several mammal groups: “The data for rodents seem pretty clear cut. Species where sexual competition between males is most intense also tend to have the longest penises. But, interestingly, a similar pattern was not detected in either primates or bats.” Understanding the reasons for these differences will require a better understanding of the precise mechanisms through which male rodents benefit from longer penises, something which comparative data alone cannot address.

Overall, the rodent with the longest penis bone relative to its body size in the study was the Western harvest mouse, Reithrodontomys megalotis. “Everything’s relative of course,” explains Dr. Ramm, “so although big for its body size the penis bone in R. megalotis is still only 7 to 8 mm long. I donít think the phrase ‘hung like a harvest mouse’ will be catching on any time soon.”

Am I in the wrong field?

As for why penis size isn’t an issue in bats, I would theorize that bats’ poor vision is a significant factor, as penis size is something that probably cannot be determined by echolocation. And primates, well, it’s clearly due to our highly advanced emotional maturity and ability to focus on characteristics that are really important when selecting a mate and companion… like breast size.

(“Penis bone”??? Mice have penis bones?)

h/t to WaPo’s Achenblog.

Entry Filed under: Science,Weirdness


  • 1. Interrobang  |  March 1st, 2007 at 5:31 pm

    Yeah, mice have penis bones. So do dogs, actually. The technical term is “os penes.” Having a penis bone makes sense if you’re a quadruped and you don’t have a big obvious vagina to aim for (like in horses or cows) and you also don’t have anything to help you achieve penetration, either.

    Wow, can you tell I’ve spent a lot of time around animal breeders?

  • 2. Glenn  |  March 1st, 2007 at 5:39 pm

    Now you’ve just gone and taken all the romance out of the equation. I don’t want to hear it. I’ll hold onto my dreams.

  • 3. Multi Medium » Juxt&hellip  |  March 1st, 2007 at 6:52 pm

    […] Should the redesign include penis bones? […]

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